In recent years, a resistance-change memory has received a great deal of attention as a candidate to succeed the flash memory. For example, a resistive RAM (ReRAM) is known as a resistance-change memory using a variable-resistance element formed by sandwiching a recording layer made of a transition metal oxide or the like between two electrodes.
The variable-resistance element of the resistance-change memory has two kinds of operation modes. In one mode, the polarity of an applied voltage is switched to set a high-resistance state and a low-resistance state. This operation is called a bipolar type. In the other mode, the voltage and the voltage application time are controlled without switching the polarity of the applied voltage, thereby setting a high-resistance state and a low-resistance state. This operation is called a unipolar type.
Each memory cell included in the resistance-change memory is formed by, for example, connecting a variable-resistance element and a diode in series between a bit line and a word line. To write-access a selected memory cell connected to a selected bit line and a selected word line, a predetermined voltage is applied between the selected bit line and the selected word line to cause a predetermined current to flow to the selected memory cell.
However, a plurality of unselected memory cells are also connected to the selected bit line in addition to the selected memory cell. Depending on the bias applied to the unselected memory cells, a leakage current derived from the unselected memory cells flows to the selected bit line. Hence, in the write, a current corresponding to a difference obtained by subtracting the leakage current from the originally set specified value is actually supplied to the selected memory cell. This makes it difficult to change the resistance state of the selected memory cell.